Plate heat exchangers

ABSTRACT

A plate type heat exchanger is provided with a permeable container in the inlet manifold formed by aligned holes in the plates. The container collects solid materials entrained in the feed liquid and may be withdrawn for emptying or replacement when full. The solids which may need to be removed before the liquid enters the heat exchanger flow passages include detached pipe line scale and live material grown in the pipework. The container may be open-topped or of closed section and means may be provided for spacing it from the edges of the holes forming the manifold.

United States Patent Wright Sept. 12, 1972 [54] PLATE HEAT EXCHANGERS 2,082,866 6/1937 Alexander ..165/1 19 X Inventor: Felix ig Copthome 3 ,51 1 ,31 1 Pedersen ..165/167 X Bank crawley, England 2,287,958 6/1942 Astle 165/167 X [73] Assignee: The A.1 .V. Company Limited, Primary Examiner prederick L. Matteson Crawley, England Filed: Oct. 17, 1969 Appl. No.: 867,278

Foreign Application Priority Data Oct. 29, 1968 Great Britain ..5 1 ,197/68 US. Cl ..l65/ll9, 165/167 Int. Cl. ..F28f 19/00 Field of Search ..165/l0l, 119, 167; 62/317,

References Cited UNITED STATES PATENTS 9/1925 Shabiro ..165/1 19 Assistant ExaminerTheophi1 W. Streule AttorneyI-lolman & Stern [57] ABSTRACT A plate type heat exchanger is provided with a permeable container in the inlet manifold formed by aligned holes in the plates. The container collects solid materials entrained in the feed liquid and may be withdrawn for emptying or replacement when full. The solids which may need to be removed before the liquid enters the heat exchanger flow passages include detached pipe line scale and live material grown in the pipework. The container may be open-topped or of closed section and means may be provided for spacing it from the edges of the holes forming the manifold.

11 Claims, 12 Drawing Figures SHEET 1 [IF 5 PATENTEDSEP 12 m2 3.690.373

sum 2 or 5 O I l PATENYEDSEP 12 m2.

SHEET Ll 0F 5 FIGIO.

PLATE HEAT EXCHANGERS BACKGROUND OF THE INVENTION This invention relates to plate heat exchangers and to methods of operating the same.

In plate heat exchangers, the transfer of heat from one medium to another occurs as a continuous process, with the two media flowing in substantially parallel flow spaces which are defined by a number of plates assembled in a face-to-face relationship. The plates are constructed such that there is provision for the entry and exit of the media to and from the flow spaces formed by this plate relationship. For thispurpose, each plate may have four holes or ports, one at each corner, two of which allow a portion of one medium to enter, flow through and exit from the individual flow space and the other two are sealed off from the flow space by a gasket such that the second medium is constrained to flow through these ports. A number or pack of plates is as sembled with the ports in alignment to provide manifolds whereby the total quantity of medium which it is desired to heat or cool enters one of the manifolds and there is a continuous reduction in the quantity flowing through as portions of medium enter the successive alternate flow spaces. The second medium flows through the intervening flow spaces. The plates are normally mounted in a frame having flow connections aligned with the port manifolds for connection to external pipework.

For reasons of design, the ports are all of the same size in any plate pack, and must be large enough to permit the entry of the whole quantity of the medium into the port manifold without undue energy loss, but as described, the quantity flowing along the manifold is successively reduced until at the end opposite the entry, the amount is reduced to the last portion of the medium which enters the last flow space, and consequently there is a reduction of velocity along the port manifold.

The entry and exit of liquid media to the port manifolds is normally arranged by providing connections of suitable size and position in the frame which is used to support and contain the plate pack, and these connections are aligned with the manifolds.

' "In certain processes, it is required to heat or cool liquid media which contains various forms of sold matter which, if permitted to enter the port manifold, would cause significant blockage of the flow space entries or if the matter is small enough to enter the flow spaces would cause significant blockage of these spaces. The provision of a separate filtering or straining device is expensive and not in all cases satisfactory, such as where loose deposits (such as pipe line scale) can form on pipe surfaces right up to the frame connection and which may be dislodged from time to time and become resident in the exchanger. Another source of such blockage is the growth of live material, such as marine fauna and flora, carried by the medium, which after becoming adherent to the pipework and increasing in size, becomes entrained in the medium and is carried through to the exchanger. Normally it is neces- SUMMARY OF THE INVENTION The present invention consists in a plate heat exchanger comprising a pack of separable and gasketted plates arranged in spaced face-to-face relationship to define flow spaces therebetween and inlet and outlet manifolds for two fluids for the flow spaces are defined by aligned holes in the plate, a permeable container providing a settling chamber being located in at least one of the inlet manifolds and extending along the manifold from the inlet end thereof whereby the fluid entering said last-mentioned manifold is fed into the container and flows therethrough before entering the flow passages between adjacent plates so that solid particles of substantial size are inhibited from entering the flow passages.

Preferably, the container is releasably secured in the manifold so that it can be removed therefrom without dismantling the pack of plates, and solid material collected therein can be cleaned out.

The reduction in flow velocity as the medium flows along the manifold assists the solid material to settle out of the medium, which is normally liquid, and be retained in the container. In view of this, the container can be open-topped over part or all of its length so the bulk of the flow into the flow spaces is not restricted by the container.

The invention further consists in operating a plate heat exchanger comprising a pack of plates in spaced face-to-face relationship to define flow spaces therebetween and having manifolds for supply and discharge of fluid media to and from the flow spaces, comprising feeding at least one of the media into a permeable container mounted in the supply manifold so that the medium flows through the container before entering the flow spaces whereby solid material entrained in said medium is retained in the container and inhibited from entering the flow space and entry passages thereto.

The invention will be further described with reference to the accompanying drawings, which show various forms of embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagrammatic elevation of a single plate;

FIG. 2 is an enlarged section on the line II-II of FIG. 1 of a number of plates assembled as a pack;

FIG. 3 is an elevation of one example of a container;

FIG. 4 is an end view of the container of FIG. 3;

FIG. 5 is a diagrammatic elevation of an assembled plate pack in the containing frame with one example of a medium connection and a container inserted along the supply manifold;

FIGS. 6 and 7 are views similar to FIG. 5 showing further examples of assembled plate packs with containers;

FIG. 8 is a detail of the container and liquid connection;

FIG. 9 is a detail of the manifold/container relationshi P IG. 10 is a detail of a container mounting;

FIG. 11 is a view similar to FIG. 9, of a further preferred embodiment; and

FIG. 12 is a view similar to FIG. 4 of an alternative form of container.

DETAILED DESCRIPTION OF THE INVENTION FIG. 1 shows a plate 1 with entry and exit ports 2 and 3 for one medium, and gasketted through-ports 4 and 5 for the other medium. A peripheral gasket 6 defines the flow space for one medium. Alternate plates in the pack are arranged so that entry ports 2 and 3 align with 7 through ports 4 and 5 as seen in FIG. 2. Also shown by FIG. 2 is the relationship between medium flowing through the port manifold by way of the entry point at X and the continual reduction of flow volume in the port by drawing ofi of equal portions entering the flow passages between plates at Y.

FIGS. 3 and 4 show one type of container, which constitutes a settling chamber, a wall 7 of which is permeable to allow liquid to pass through but to retain solid particles or bodies of a size larger than a given limit. In this embodiment the container is in the form of wire mesh.

FIG. 5 shows an assembled plate pack 8 contained in a frame 9 having frame connections aligned with the port manifolds and showing connecting pipework forming a supply line 10 to one of the port manifolds. Port 2 of FIG. 1 has been used in this example. A container similar to that of FIG. 3 is shown installed in the port manifold. Liquid and solids entering through the supply line 10 will pass into the container within the port manifold. As the quantity flowing is successively reduced, the solids will tend to settle out in the container, particularly at the end farthest from the entry where the quantity flowing is much reduced. The liquid medium passes easily through the container wall as required.

The connections may be readily arranged in such a way as to permit extraction of the container from time to time as required without the necessity of dismantling the frame and plate pack. For example, a blank flange at 11 can be removed, the container withdrawn, emptied and replaced, the blank flange replaced and the exchanger restored to operation. in a much shorter space of time than would be required for dismantling the whole plate pack assembly. This flange 11 may be bolted on, but for ease and speed of removal, it may be securedby a quick-release clamp.

FIG. 6 shows an alternative arrangement where the medium is arranged to flow through two sections of plate pack in succession. In this case the container cannot be withdrawn at the opposite end to the medium inlet but by using a tee-piece connection 12 the container may be withdrawn from the same end of the port manifold as the medium inlet connection.

FIG. 7 shows a further alternative where the inlet connection is positioned at the top of the exchanger. In

' this case, a connection is made between the far end of the inlet port manifold and the outlet from the exchanger. A small proportion of medium entering is permitted to flow from the entry manifold, with the amount beingcontrolled by a valve 13 such that solid to some other pattern, e.g. circular perforations in sheet metal.

A container which is fully circular in cross-section is therefore a hollow cylinder the wall of which is permeable as described and one end of which preferably closed, with the opposite end being open to permit the entry of the medium into the container. A circular container may be of such a size in cross-section that the distance Z in FIG. 8 from the container wall to the inside surface of the liquid connection is small compared to the size of perforation in the container wall whereby only particles which are considerably smaller than the given limit of those particles retained in the container can enter the manifold without passing through the container wall. In the same manner it is a simple matter to make the container slightly smaller in cross-section than the manifold in which it is situated so that longitudinal insertion and withdrawal is made easy as shown by the gap W in the detail of FIG. 9.

' Under certain conditions of operation, the limit of particle size may be very small and hence the container wall perforations are small so that it is preferable to provide a seal at the open end of the container engaging with the liquid connection wall.

An example of this is given in FIG. 10 where the open end of the container is attached to a ring 15, in the periphery of which is formed a housing groove which contains a resilient gasket 16. By co-operation with the inside surface of the connection, a seal against medium flow is provided as for example by the well known principle of rubber O-ring seals. In this embodiment, all the medium flowing along the supply line 10 is constrained to flow through the ring 15 and consequently can only enter the plate passages by way of the container wall.

In FIG. 10, the seal ring 15, and seal 16 are cooperating with the bore of the connecting pipe. This is perfectly feasible but in practice it is easier to provide a machined bore of accurate diameter in the frame mounted connection so that the surface on which the O-ring seals is entirely associated with the frame.

As shown in FIG. 1 1, in order to provide location of a container 21, it may be provided with a plurality of circumferentially spaced rods 22, one of which is illustrated, extending over all or part of its length. The rods 22 are provided at intervals with localized bushings 23 which engage with the ports of several adjacent plates to locate and centralize the container 21 in the port manifold. The local interruption of flow into the spaces between the plates is a slight disadvantage but is not too great if the bushings are not too numerous or too large. The rods 22 are anchored in a ring, such as the ring 15 of FIG. 10, to attach them to the container 21.

The bushings 23 may entail some increase in the clearance W which they span, but the ring 15 may be dimensioned accordingly to provide a close fit in the inlet pipe, preferably sufficiently close to eliminate the I need for a sealing ring 16.

It is possible to add to the container a means for withdrawal such as a handle or hook, or in a further alternative, the end of the container may be secured to the blank flange 1 1 for purposes of location.

Various othermodifications may be made within the scope of the invention.

I claim:

1. In a plate type heat exchanger constituted by a pack of separable and gasketed plates arranged in spaced face-to-face relationship to define flow spaces therebetween and inlet and outlet manifolds for two fluids for the flow spaces being defined by aligned holes in the plates: the improvement that a permeable container providing a settling chamber is located in at least on of the inlet manifolds, said container extending along the manifold from the inlet end thereof whereby the fluid entering said last mentioned manifold is fed into the container and flows therethrough before entering the flow passages between adjacent plates so that solid particles of substantial size are inhibited from entering the flow passages.

2. The plate heat exchanger as claimed in claim 1, in which means releasably secures the container in the manifold so that it can be removed without dismantling the pack of plates.

3. The heat exchanger as claimed in claim 2, in which the manifold has a closed end remote from the inlet end and in which a removable cover is provided to openably close said remote end to allow access to the interior of the manifold for removal of the container.

4. The heat exchanger as claimed in claim 2, comprising a tee piece connection having a stem connection and two aligned branch connections, the stem connection being connectable to external pipework, one of the branch connections being connected to the inlet end of the manifold and a removable cover being provided on the other branch connection for access to the container.

5. The heat exchanger as claimed in claim 1, in which the said manifold has an extension remote from the inlet end and having an external connection, with the container extending through the manifold into the extension.

6. The heat exchanger as claimed in claim 1, in which the container is open-topped over at least part of its length.

7. The heat exchanger as claimed in claim 1, in which the container is a cylindrical hollow body of permeable material. 1

8. The heat exchanger as claimed in claim 7, in which each hole has a rim and wherein localized spacers are provided to engage the rims of the holes to locate and centralize the container in the manifold.

9. The heat exchanger as claimed in claim 8, comprising a plurality of longitudinally extending rods spaced circumferentially about the container, with said rods carrying bushings to act as said localized spacers.

10. The heat exchanger as claimed in claim 1, in which the container is provided with a seal at the inlet end whereby fluid entering a supply conduit cannot bypass the container.

II. The heat exchanger as claimed in claim 1, in which the container is located in the manifold inlet end with a clearance less than the particle size normally passed by its permeability whereby solid particles of significant size entrained in the fluid cannot by-pass the container. 

1. In a plate type heat exchanger constituted by a pack of separable and gasketed plates arranged in spaced face-to-face relationship to define flow spaces therebetween and inlet and outlet manifolds for two fluids for the flow spaces being defined by aligned holes in the plates: the improvement that a permeable container providing a settling chamber is located in at least on of the inlet manifolds, said container extending along the manifold from the inlet end thereof whereby the fluid entering said last mentioned manifold is fed into the container and flows therethrough before entering the flow passages between adjacent plates so that solid particles of substantial size are inhibited from entering the flow passages.
 2. The plate heat exchanger as claimed in claim 1, in which means releasably secures the container in the manifold so that it can be removed without dismantling the pack of plates.
 3. The heat exchanger as claimed in claim 2, in which the manifold has a closed end remote from the inlet end and in which a removable cover is provided to openably close said remote end to allow access to the interior of the manifold for removal of the container.
 4. The heat exchanger as claimed in claim 2, comprising a tee piece connection having a stem connection and two aligned branch connections, the stem connection being connectable to external pipework, one of the branch connections being connected to the inlet end of the manifold and a removable cover being provided on the other branch connection for access to the container.
 5. The heat exchanger as claimed in claim 1, in which the said manifold has an extension remote from the inlet end and having an external connection, with the container extending through the manifold into the extension.
 6. The heat exchanger as claimed in claim 1, in which the container is open-topped over at least part of its length.
 7. The heat exchanger as claimed in claim 1, in which the container is a cylindrical hollow body of permeable material.
 8. The heat exchanger as claimed in claim 7, in which each hole has a rim and wherein localized spacers are provided to engage the rims of the holes to locate and centralize the container in the manifold.
 9. The heat exchanger as claimed in claim 8, comprising a plurality of longitudinally extending rods spaced circumferentially about the container, with said rods carrying bushings to act as said localized spacers.
 10. The heat exchanger as claimed in claim 1, in which the container is provided with a seal at the inlet end whereby fluid entering a supply conduit cannot by-pass the container.
 11. The heat exchanger as claimed in claim 1, in which the container is located in the manifold inlet end with a clearance less than the particle size normally passed by its permeability whereby solid particles of significant size entrained in the fluid cannot by-pass the container. 